Glass bulbs and the like containers provided with self-breakable necks

ABSTRACT

A METHOD AND MEANS FOR OBTAINING A SELF-BREAKABLE BULB OR PHINAL, THAT IS A BULB OR PHIAL REQUIRING NO FILE FOR CUTTING IT OPEN; TO THIS END, THE EDGE F A BLADE OF SILVER, ALUMINIUM OR ALUMINIUM ALLOY IS URGAED AGAINST THE NECK OF THE CONTAINER DURING ITS COOLING SO AS TO LOCALLY INCREASE ITS CAPACITY OF THERMIC DISSIPATION AND TO CNSEQUENTLY PRODUCE AN INTERNAL STRAINING LEADING TO A GREATER BRITTLENESS. ADVANTAGEOUSLY THE BULB OR THE LIKE CONTAINER IS CAUSED TO REVOLVE ROUND ITS AXIS DURING THE PROCEDURE SO AS TO ENSURE AN ANNULAR MARKING WHEREBY THE NECK MAY BE BROKEN IN A CLEAN MANNER BY A FLEXIONAL STRESS EXERTED ON IT WHATEVER THE DIRECTION OF THE STRESS MAY BE.

June 29, 1971 GUIRlEc 3,589,884

GLASS BULBS AND THE LIKE CONTAINERS PROVIDED WITH SELF-BREAKABLE NECKSFiled March 5, 1969 K4 YMOA/A Gum/Ea United States Patent 3,589,884GLASS BULBS AND THE LIKE CONTAINERS PROVIDED WITH SELF-BREAKABLE NECKSRaymond Guiriec, Longjumeau, France, assignor to Socit a ResponsabilitLimite Laboraver, Longjumeau, France Filed Mar. 5, 1969, Ser. No.804,554 Claims priority, application France, Mar. 5, 1968,

Int. C1. C63]; 21/00 US. Cl. 65-105 2 Claims ABSTRACT OF THE DISCLOSUREA method and means for obtaining a self-breakable bulb or phial, that isa bulb or phial requiring no file for cutting it open; to this end, theedge of a blade of silver, aluminium or aluminium alloy is urged againstthe neck of the container during its cooling so as to locally increaseits capacity of thermic dissipation and to consequently produce aninternal straining leading to a greater brittleness. Advantageously thebulb or the like container is caused to revolve round its axis duringthe procedure so as to ensure an annular marking whereby the neck may bebroken in a clean manner by a flexional stress exerted on it whateverthe direction of the stress may be.

The present invention has for its object glass bulbs, phials and thelike containers provided with one or two necks adapted to be broken soas to allow the contents to be used. "A

To open such bulbs a slight cut is generally made by means of a fileafter which a flexional stress is exerted on the outer end of the :bulbbeyond the neck so as to open the latter. It has already been proposedto cut out the requirement leading to the use of a file by providingself-breakable bulbs. The French Pat. 1,093,767 dated Feb. 22, 1954,discloses a method for executing such self-breakable bulbs provided witha throttled neck by first weakening the bulb at a point of the neck bymeans of a transverse scratch or notch on the outer surface of the neck.The location of the notch or scratch is advantageously defined by acolored product which is caused to melt over the surface of the neckduring the annealing procedure. Said prior patent also discloses theproduction of internal stresses within the glass structure by applying acold implement over the neck which is still in a hot condition or else aproduct adapted to melt while its coetficient of expansion is higherthan that of the bulb. These last two modifications have been referredto however as less satisfactory than the scratching of the neck and infact this last method was considered as the sole one suitable in thecase of conventional bulbs with a single neck. It requires however theuse of a colored product which can melt easily and which melts duringthe annealing procedure, which means auxiliary operations and leads tothe production of exaggeratedly brittle bulbs or conversely ofunbreakable bulbs according as to whether the notch is too deep or tooshallow.

The French Pat. 1,040,588 dated July 27, 1950, disclosed on the otherhand the execution of self-breakable bulbs by means of a stressing ofthe glass forming the neck as provided by the application, over acomparatively reduced area or along a line, of a readily meltablematerial the shrinking coefiicient of which differs from that of glass,said material being caused to melt during the annealing of the bulb.This method requires an objectionable annealing which leads to furtherwork and handling and "ice such further handling may be a cause ofbreaking and increase in cost.

The present invention has for its object to cut out the above drawbacksby producing through a single simple operation the inner stressing ofthe glass and the marking of the section to be broken, before usewithout any other ancillary operations.

The method provided by the invention consists in applying against the.glass forming the bulb neck, while the bulb is at a temperature rangingbetween about and C. a thin annealed blade or section of silver,aluminium or of an aluminium alloy.

Said metal blade or section which is laid on the bulb at roomtemperature produces a straining of the glass material which furthersthe breaking of the neck and leaves an indelible mark on the glass; thiscuts out the necessity of any subsequent marking by means of a fusiblematerial, which marking is always a lengthy. operation and requires anannealing, while furthermore it risks being inaccurate.

The method according to the invention provides thus multiple advantageschiefly as concerns speed and simplicity when compared With priormethods.

According to a preferred embodiment, the method consisting in strainingand marking one or both ends of the bulb is incorporated with the actualproduction of the bulb and is performed during the cooling stagefollowing the drawing out and cutting off of the bulb just before theejection of the finished bulb.

According to an auxiliary feature of the invention, the thin blade isapplied over the bulb while the latter revolves through at least onerevolution round its axis so as to leave a mark surrounding entirely theneck of the bulb, whereby this neck may be readily broken off by abending stress exerted in any direction whatever.

The machine for executing the method according to the invention isconstituted by a bulb-producing machine of the so-called Well-knownmerry-go-round drawing out type wherein the glass tubes are heatedlocally and then drawn out to form the necks of the bulbs or phialswhich are then cut off, one end thus formed being closed and the otherremaining open. According to the invention, said machine is provided ata point ahead of the drawing out station with one or two blades made ofannealed silver, aluminium or aluminium alloy and the edge of which isurged elastically against the path followed by one or both bulb necksformed by drawing the successive bulbs out of the original tube.

The invention will now be disclosed with further detail, reference beingmade to the accompanying drawings wherein:

FIG. 1 is an elevational view of a bulb obtained in accordance with myinvention,

FIG. 2 is a diagrammatic elevational view of the station of thebulb-producing machine at which a metal deposit is obtained so as tomark the necks of a bulb, said cross-section being executed along lineII-II of FIG. 3.

FIG. 3 is a diagrammatic plan view of the station as seen under thehorizontal plane designated by III-III in FIG. 2. The bulb 1 is of thestandard type including two straight tapering necks, the end of the neck2 being closed by melting said end 2 to form a bead 3 on the latterwhile the other end 4 remains open for its subsequent filling beforewelding. According to the invention, each neck of the bulb is providedwith annular peripheral traces of annealed silver, aluminium oraluminium alloy.

The merry-go-round of the conventional bulb-producing machine includes alower annular plate 6 and an upper annular plate 7, both plates beingdriven into rotation in the direction of the arrow F while thetubeclamping members 8 and 9 are driven in the direction of the arrows;f. The members 8 engage the original glass tubes 10 while the members 9engage the already formed bulb, the neck-shaped end 2 of which isalready closed by welding. The part of the tube 10 extending between thetwo tube-clamping members has been heated at a preceding station bymeans of a blow-pipe and has been stretched so as to form the neck 4 onthe bulb 1 and the neck 2 on the lower end of the remainder of the tube10, the connection between the tube and the bulb being cut off justunder the lower sealed end of the tube 10'.

In registry with the cooling station illustrated in FIGS. 2 and 3, atwhich station the temperature of the glass is equal to 150 C. orthereabouts, there are fitted two silver blades '11 extending in thehorizontal plane which has been selected for the location of thebreakable section of the neck during operation. These blades are carriedby horizontal arms pivotally secured at 13 and urged towards thevertical axis of the glass tube and bulb by the springs 14, the movementof said arms 12 being limited by stops 15.

The neck 4 of the bulb 1 and the neck 2 at the lower end of the tube 10hold the blades 11 against further inward motion so that said bladesleave on the glass by reason of the rotary movement and temperature ofthe latter a clear apparent trace 5. Such a metal trace furthers heatexchange with the outer atmosphere whereby a local cooling of theunderlying glass section is accelerated and consequently an inner strainappears in said section. When a flexional stress is exerted on the tipof a bulb when closed, the neck breaks along a clean line defined by thetrace 5.

Obviously numerous modifications may be brought to the above embodimentgiven by way of example, without widening the scope of the invention asdefined by the accompanying claims.

What I claim is:

1. A method of providing a self-breaking neck on a hollow glass article,comprising urging a thin member of a metal selected from the groupconsisting of annealed silver, aluminum and aluminum alloy against theneck of a hollow glass article while the neck is at a temperature ofabout 100 to 180 C. and rotating said article through at least onecomplete rotation about the axis of its neck during the application ofsaid member so as to deposit on the glass a band of said metal thatencircles the neck and that accelerates local cooling of the underlyingglass thereby to form on said neck an annular stressed section thatallows the neck to be broken readily by flexural stresses in anydirection.

2. A method as claimed in claim -1, and forming said article from aglass tube and drawing out and cutting off the article from said tubeand thereafter performing said urging and rotating steps while thearticle is cooling.

References Cited UNITED STATES PATENTS 2,641,870 6/1953 Eisler 65-174X2,918,753 12/1959 Pichter 65-174X 3,215,345 11/1965 Ferguson 65-174lUXFOREIGN PATENTS 409,283 4/1934 Great Britain 65-108 815,259 6/1959 GreatBritain 65-108 545,605 7/1956 Italy 65-109 608,026 9/1960 Italy 65-1741,270,841 7/1961 France 65-105 644,410 3/1937 Germany 65-115 FRANK W.MIGA, Primary Examiner US. Cl. X.R.

